The late 1990s saw the start of an immense building boom in cruise ships. Nineteen new ones arrived in 2001, and nearly 40 more are planned for the next two years. Most of these are enormous vessels, capable of accommodating more than 2,000 passengers. Filling all those cabins makes for an extremely competitive business, says Birch Coffey, an architect for Celebrity Cruise’s four new Millennium-class ships (a designation that, as with battleships, refers to the name of the first one delivered).